Telephone-testing system.



i '11. c. GOLDRIGK;

TELEPHONE TESTING SYSTEM.

APPLICATION FILED TIOV. 14, 190-1.

Patented Feb. 2, 1909.

1: "ml! FBTIRS ca, wasmuuwn, n. c.

UNITED STATES PATENT oFFroE. iii

HARRY G. GOLDRIOK, OF INDIANAPOLIS, INDIANA, ASSIGNOR TO KELLOGG SWITCHBOARD & SUPPLY COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

TELEPHONE-TESTING SYSTEM.

Specification of Letters Patent.

Patented Feb. 2, 1909.

i To all whom it may concern:

Be it known that I, HARRY O. GOLDRICK, a citizen of the United States, residingin Indianapolis, county of Marion, and State of Indiana, have invented certain new and useful Improvements in Telephone-Testing Systems, of. which the following is a specification.

In the present application I have disclosed a testing system for telephone lines, which in the form that I prefer to use includes a tip contact upon the testing lug of the operators connective circuit whic is insulated from the talking contacts thereof, and which is connected by a separate conductor with the apparatus by which the test is made known to the operator.

It is usual to employ one of the talking contacts of the connecting plug and a portion of one of the talking strands for busy testing purposes but in my arrangement the testing contact and strand are entirely separate from the talking circuit whereby the apparatus may be simplified and the testing operations carried out in a simple and efiicient manner.

The preferred form of my invention is illustrated in the accompanying drawing in which: I i p Figure 1 is a diagram of a tele hone trunk circuit and subscribers line wit which the incomingend of the trunk is adapted to 00+ operate; Fig. 2 is a detailed view of a springjack and the inserted testing plug, the jack being of the form shown in Fig. 1 as connected with the subscribers line, and Fig. 3 is a diagram of an operators cord circuit and a subscribers line circuit, the latter being of the so-called 2-wire type in which the test rings of the springjacks of the lines are connected with the talking circuit during conversation.

Referring to Fig. 1, the subscribers line extends in two limbs 2 and 3 from the sub: scribers station A to the central ofiice C where the line is provided with a lurality of sprin jacks such as J andJ in t e multiple switc board. At the subscribers statlon with a common lead 13 extending live pole of the central common .When'said cut-ofi' relay R is ener Atthe same time the local circuit for the transmitter 8, the local battery 9 and the primary winding of the induction coil 7 is completed. At the central office the line conductor-2is normally grounded but upon the actuation of the cut-off relay R the said line is disconnected therefrom and connected with the conductor 10 leading to the tip contact of the springjacks J J etc. The line conductor 3 is normally connected by means of conductor 11 with the line signal S, Whose other terminal is joined by a conductor 12 from the attery B. ized the line conductor 3 is disconnected 'rom the conductor 11 and connected with the conductor 14 leading to the sleeve contacts 9' of the springjacks. The test rings 3' of the springjacks are connected together and t ence by wire 15 with the forward contact of a third spring 16. of the cut-off relay R, which spring is in turn grounded through a suitable resistance 17. Thecut-oif relay R is connected upon one side by conductor 18 with the battery lead 13 and upon the other side by wire 19 leadin to auxiliary springs j of the springjack w ich are thrown intov connection with ground contacts when connecting plugs are inserted in the acks. The trunk circuit shown in this fi ure is rovided at the outgoing end, which is locate at a different switchboard section or oflice D, with a springj ack J and a retardation coil 20 legged to ground from the sleeve contact of the ac 1 .At the office 0 the tip and sleeve sides 21 and 22, respectively, of the trunk, are joined together by the windings w and w of the repeating coil W and an interposed condenser c. The conductor 22 is extended by conductor 23 to one terminal of the trunk relay 1" and whose other terminal is joined by conductor 24 with a spring 28 of a relay r which may be termed the tip relay, and the normal contact of which spring is connected by a wire 25 with the ti conductor 21 of the trunk. The trunk att is end of-the office is provided with a flexible strand of which the conductors t and 8 lead to se arate contactsupon the connecting plug P w ich is adapted to be inserted in the jack J or J The opposite ends of these strands or flexible conductors are joined through windings w and w of the repeating coil W and a suitable condenser c. The tip relay is joined upon one side by conductor 26 with the tip trunk cord strand between the coil w and the condenser c and u on the other side by conductor 27 with the live pole of the battery B. The iorward contact of spring 28 or said'relay r is grounded while its spring 29 is connected by conductor 30 with said conductor 27, the for ward contact of which is joined by conductor 31 with one side of the disconnect signal S preferably in the lorm of a small incandescent lamp. A relay 7, which for convenience is called the sleeve relay, is joined upon one side by conductor 32 sleeve strand of the cord 8 between the winding to and condenser c and upon the other side by conductor 33 with one terminal of the said subscriber. it found busy. however, the operator at the D oilice and the calling subscriber are informed that the line is busy. ihis testing operation is expeditiously caried out by touching the tip of the plug l to one of the test rings j of the spring-jack ol the wanted line that appears upon her section of the board. if idle it will be noted that th e test rings are isolated. from ground or other connections but when the line is busy the eut-oli' relay R is operated and the test rings are connected to ground. 'lhc touching ol' the tip of the plug to an idle line therefore, prowith the ringing signal S also in the form of a small incandescent lamp, and thence by conductor 34 to the forward contact of grounded. spring 35 of the trunk relay 7. This sleeve relay r is provided with a spring 36 connected by conductor 37 with the battery lead 13 and adapted to close upon a forward contact which is connected with one terminal of the winding of said relay. connected with conductor 01 and with one terminal of the disconnect signal S and its normal or back contact is oined to second terminal of the ringing signal S A ringing generator is adapted to be connected with the talking contacts p and p of the plug P through the medium of the ringing key springs 40, one pole of said generator being grounded at 41. For testing purposes a tip contact p of said plug P is connected by means of a flexible strand 42 with the tertiary winding of the operators induction coil 43 and thence by con ductor 44 with the battery lead 13. The operators transmitter 425, retardation coil 46, condenser c and the secondary winding of her induction coil, partake of the usual arrangement, her head receiver 47 and a suitable condenser c and the secondary of her induction coil likewise being arranged in the usual manner and connected with order wires 48 leading to the opposite end of the trunk as is customary.

I have not shown the cord circuit or the subscribers lines at the o'liice D but the type of circuit and snbscribers line shown in Fig.

3 are adapted to be usedwith the trunk of Fig. 1. 'lhis trunk is adapted for the usual method of operation; that is, a call being received at the office D for a subscriber whose line terminates at the office C, the operator at the former office depresses her order key and informs the operator at the oiliceC of the connection desired. The operator at the latter office nominates the trunk to be used and immediately tests the condition of the Wanted line. If the line is found idle the calling'plug is inserted in the jack of the line and the ringing generator operated to call the A second spring 38 is duces no click in the operatofis receiver, since a complete circuit is not estahltshed', but in case the line is busy a crunplete circuit is established from the live pole oi the battery 13 over conductors 323 and all, the tertiary winding of the operators induction coil 43, conductor 42, tip y) oi the plug, test ring j oi the jack, conductor 1?). spring it til the rclaydt, and thence through the resistance coil 17 to ground. 'lhe current in this path inductively causes a clicl: in the ope 'ators receiver and she thus inlorrued that the line is busy. Assuming that the line is found idle the testing plug is inserted in the springjack, the contacts p and p oi' the plug ongaging the correspoinling contacts j and j" oi the springjaeh. l he tip contact of the plug. however, does not engage any of the contiu'ts of the springjacl: and therel'ore is entirely insnlated and isolated during ronrersatiiin. 'l his arrangement is more fully indicated in Fig. 2 in which the jltCli springs j and j are shown as being insulated by the stud 50 and. secured in position upon the support .31 by a suitable screw 52. 'l he jack ring j" is connected with the same support by an intervening strip oi metal 53. The plate 5a is connected with ground and is ICl'M'OSQIllWl. in the diagram by the grounded hacl; contacts of springs j. 'lhe test rings 7' are larger than the contacts oi? the plugs and in addition the sleeve of the plug at this point is grooved, so that said rings do not touch the sleeve of the plug when the latter is inserted in the jack. lhis ring is connected by the Wire or metallic strip show i in dotted lims leaning to the fourth terminal at the rear of the support 51.. .lhus the tip contact p of the plug does not touch any contact while inserted.

To briefly illustrate the operation of the system shown in Fig. i, aside from its testing features, it may he stated that the corn ncction oi the cord circuit with tho outgoing end of the trunk results in energizing the trunk relay 1" by current from said. cord circuit, as for instance, from hatt y B. The insertion of the plug P oomph tor a path for current through the tip relay i from the live pole of the battery B. out ov the tip strand t of the tip cord, and thence by way ol the tip side of the telephone line through the vented from operating.

receiver which completes a .path for current from the battery B over the metallic telegrounded in ell;.5 ,.at;the, substation, thus .energizing said relay also,-;Whi ch results in closing a path for current throughrthe ringing lamp 1 8 which 3 path maybe traced. from. the live pole of said battery ,B by conductors ,27 and 30, spring 29, conductor 8,1,ispring'38;of;re layr lamp S conductor Maud spring 35 of relay-r to ground. The latter relay, it should be explained, is now energizediby current overthe sleeve side ofthe trunk and through the spring 28 of relay r and its forward contact to ground. The ringing signal S is therefore lightedand the signalS; is pre- This condition is maintained untilthesubscriber takes up his phone line to the substation asbefore traced, but instead of returning through the ground ,ed hell it now returns over the sleeve side of the telephoneline, the sleeve strand 8 of the trunk cord and thence through conductor 32,

relay r conductors 33 and 34, and spring 35 toground. This results in energizing the relay 9"? which opensthe circuit of the ringing signal S thusretiring the same and indicating to the 1 operator that the subscr ber has responded andat thesame time closes a looking circuit forjitselffrom thelive-poleof the.

battery overconductors13 and37, spring 36,

'its forward; contact, thence'through the winds ing of :therelay m conductors 3 3 and 34. and throughthe spring 35 to ground. It will be noted that this path over conductors 13 and 37 is in parallel with the path for current through the relay r and out over the telephone line and back to the,central office over conductor 32, so that said path short circuits the former path over the telephone line, deprives the same of current and prevents the tip relay r from being longer 6113f".

gized, At the same time the relay 1" is not deenergized since its locking circuit is com pleted and remains completed as long as the trunk relay 1" is energized. The trunk relay r is now energized over the metallic outgoing end of the trunk, which operates the supervisory signaling apparatus in the cord circuit at said end to notify the operator that the subscriber has responded. At the termination of the conversation relay r is a ain energized through the grounded signa ing talking circuit. with an answering plug P and a calling If other W6ll-kI1OWI1 manner.

with line; circuits provided with two-point :jacks and-with cord circuits of 1 the -=tWostrandtype, as indicated in :Fig. 3. In, this figure the subscribers line L extendsfrom the subserib eris station ;which is provided with the 1 ordinary arrangement for common battery talking, to the; central oflicewhere the usual line signals S two-point springjacks J and J cut-ofi relay R and line relay R are provided, the said cut-off relay being,

operated bylcurrent .over a portion of the The cord: circuitis provided plug B eachnhaving two talking contacts adapted to register with the corresponding.

contactsof-the ,springjacks. The usual batteries B and 13 are associated with the cord circuit for the operation of the supervisory apparatus, including signals S S controlled by the supervisory relay 1", r", r..

and W. This operation is well understood and needs no-further description. The testing plugP however, is provided with a special tip contact ,p which 1s msulated from the talking contacts of the plug and which isarranged as in Fig. 2 not to engage any of the contacts ofthejack when inserted therein. Thistip contact is joined bya conductor 6O individually to the calling cord through a common retardationcoil 61 and the tertiary winding of the operators induction coil to ground. When an idle line is tested, therefore, by touching the tip of the calling plug P to the test ring of one of the jacks, no flow of current results since both the tip of theplu and the test ring are connected with groun and are therefore at the same potential. The insertion of a plug in one of the jacks, however, connects the test rings with the live pole of one of the batteries B or B and the application of the grounded testing tip of a plug to one of the test rings results 1n a flow of current through the tertiary winding of the operators induction coil and therefore causes a click in her receiver. This flow of current may be reduced to any desired extent by means of the retardation coil 61 or in any When the plug is inserted as stated above the tip contact does not touch the talking contacts of the jacks and the testingstrand for that particular cord circuit is not included in any circuit. As shown by the branching lines from the point 63, the retardation coil 61 and operators outfit are preferably common to a certain number of cord circuits, preferably to all of the cord circuits at the o erators position; and as similarly indicate in Fig' 1, the strand 42 is individual to the cord, but

the operators set is common to the operators position.

"While I have thus described one practical method of carrying out my invention, 1

would have it understood that it is not to be so limited in all respects as various changes .may be made therein and still come within its scope and principle.

I claim:

1. The combination with a telephone line, of a testing circuit to determine the idle or busy condition of said line, a conducting plug with which said line is adapted to be connected, a central source of current to furnish current for conversation and for testing, said plug having two contacts adapted to connect one with each limb of the line, and a third contact connected with said testing circuit but not adapted to connect with any surface while the other two contacts of said plug are in connection with said line, sub stantially as described.

2. The combination with a telephone testing system, of a line terminal and a cord terminal; tip, ring and sleeve contacts for said cord terminal, and ring and sleeve contacts for said line terminal ada ted to register with like contacts of said cor terminal, a central source of current to furnish talking current to the line during the connection of the cord with the line, a testing circuit completed by the contact of said cord termianl tip with said line terminal sleeve and means whereby said tip terminal will not register with any contact of the line-terminal while said ring and sleeve contacts are in connection, sub stantially as described.

3. The combination with. a telephone line, terminating in a plurality of jacks at the central otfice, a central source of current to furnish current for conversation, of a testing circuit adapted to be completed through one of the contacts of said jacks, a test receiving device in said circuit said device being common to a plurality of cord circuits, the testing circuits of said cord circuit being integral and free from series contacts during testing, substantially as described.

4;. In a telephone system, the combination with a metallic telephone line terminating at the central office in a two-point jack, one contact of said jack being both a testing and a talking contact, a cord circuit, a testing contact upon the calling plug of said cord circuit, said contact being entirely out of metallic connection with the jack when the )lug is inserted therein, substantially as described.

5. The combination with a telephone line, of a plurality of jacks having contacts normally disconnected from the limbs of the telephone line, a cut-oii relay for the line adapted when actuated to connect the limbs of the telephone line with said contacts, a cord circuit to connect with the line, a calling plug for said cord circuit, said plug having two contacts adapted to register with. the contacts of the jack which are connected with the limbs of the telephone line by the actuation of the cut-oil relay, and a third contact independent from the contacts of the jack during conversation, and a test receiving device permanently connected with said third contact, substantially as described.

In witness whereof, I hereunto subscribe my name in the presence of two witnesses.

HARRY C. GOLDRICK.

Witnesses:

C. J. LANGDON, WM. E. RoBEY. 

